SOME CONCEPTS IN THE THEORY OF LEXICAL DIFFUSION

In the theory of lexical diffusion it is assumed that sound change is lexically gradual, a few lexical items being affected at a time (Wang 1969). More specifically, in the lexicon of a speaker experiencing the sound change A+ B, there will be three classes of items: 1) those pronounced only as A; 2) those pronounced sometimes as A, sometimes as B; and 3) those pronounced only as B. Suppose that sound A is a member of the phono 1 ogi ca 1 category A ·undergoing the change A + B, we can refer to the history of change in this member A in terms of three periods: the pre-change period in which A remains A; the change period in which A appears sometimes as A, sometimes as B; and the post-change period in which A appears only as B. We may ca 11 forms of i terns appearing in the pre-change period unchanged forms (A's), forms appearing in the post-change period changed forms (B's) and forms appearing in the change period synchronic variations which are sometimes changed forms and sometimes unchanged forms (A~ B's). The correspondence between these forms and periods can be summarized in Table I below: